It can be appreciated that fluid treatment systems with one or more monitoring ports have been in use for years. Existing products commonly found in the market-place include air and water treatment devices utilizing ultraviolet light (UV) as a means to inactivate, reduce, eliminate, convert, or destroy some portion of undesirable contaminant within the fluid being treated. Other products commonly found in the market-place include vapor and liquid processing systems utilizing UV light as a means to cause or enhance a chemical reaction within the fluid being processed. The use of UV as a useful agent for the aforementioned purposes has been well demonstrated and documented in the art.
One of the factors that determines the effectiveness or capacity of such treatment and processing systems is the amount of UV light passing through the fluid, and since that amount can be adversely affected by one or more factors it is useful to have at least one sensor for indicating the amount of UV within the fluid treatment zone: such sensors typically measure the rate of UV energy falling on a surface area within the fluid treatment zone, with units of power per unit area (eg: Watts per square centimeter abbreviated as W/sq.cm). Information emanating from such fluid treatment process sensors can be used to either manually or automatically control the process or signal an alarm as to a deficiency in the process.
Common UV sensors typically install into a port in a fluid treatment vessel and utilize a window made from material that is transparent to UV light, for example quartz glass, sealed to prevent fluid from escaping the vessel and to isolate the fluid being treated from a UV sensing element and its related electronic signal processing components. The UV-transparent window may be fixed in a sealed manner to a treatment vessel's UV monitoring port so that a sensor may be removed without risk of fluid escaping the through the empty port, or the sensor may contain its own integral sealing window so that the port does not require a fixed window.
Systems are also known in the art which utilize multiple UV-transparent windows: for example one transparent window sealingly fixed to the monitoring port and at least one additional window integral with the sensor. UV light from within the fluid treatment zone passes through a UV-transparent window and falls on a UV sensitive element, such as a photodiode, and the resulting signal from the UV sensitive element will give an indication of the amount of UV light within the treatment zone. Since the signals from common UV-sensitive elements are typically small, they can be amplified, processed, and interpreted by techniques well known in the art. Alternatively, the UV-light may at some point fall on a phosphor-type material that converts the UV light into at least one different wavelength of light which then falls upon a different type of light-sensitive element, but there will still typically be a transparent window between the fluid treatment zone and the light-sensitive element. It is common, although not universally required, to have some form of calibrated reference sensor which can be used periodically to check that the system's regular “duty” UV sensor is functioning properly and providing a signal which corresponds correctly to the amount of UV light. Such reference sensors are often designed such that, after removal of the regular sensor, they can be inserted into the same port as the regular sensor. An additional unique port may be included in the treatment vessel to allow periodic insertion of a reference sensor. The successful monitoring of UV light within a treatment vessel as described above typically requires periodic and thorough cleaning of a transparent window surface in contact with the fluid so as ensure that fouling deposits are not blocking some portion of UV light passing through the window to the UV sensor and causing erroneous low readings from the UV sensor.
The main problem with conventional fluid treatment system monitoring ports that do not include a sealingly fixed barrier, such as a transparent window in a UV monitoring port, between the fluid and sensor is that in order to remove the sensor for periodic cleaning, calibration, other maintenance, or to insert a reference sensor, it is necessary to shut off fluid flow to the treatment vessel or drain some portion of fluid from the vessel so as to prevent undesirable escape of fluid through the empty port. It can be seen that this main problem, specifically the requirement to interrupt the fluid treatment or process to prevent undesirable escape of fluid through the empty monitoring port while performing some sort of sensor maintenance or reference check, persists with ports and sensors intended for monitoring parameters other than UV light.
While conventional UV monitoring ports that do include a sealingly fixed transparent window between the fluid and sensor may allow removal of a sensor while preventing escape of fluid, such arrangements do not provide for convenient access to the window surface in contact with the fluid, and the task of removing such a conventional fixed window invokes the main problem that it is necessary to shut off fluid flow to the treatment vessel and drain some portion of fluid from the vessel.
Another problem with conventional fluid treatment systems that include multiple UV monitoring ports with each port containing its own sealingly fixed window, is that each window may accumulate a different amount of fouling and invalidate the reading from one or more sensors and hence defeating at least one purpose of having multiple sensors, for example the comparison between a duty sensor and a reference sensor.
Yet another problem with conventional UV monitoring ports is that when the sensor has been removed it may be possible to expose a nearby person to harmful UV radiation emanating from within the treatment vessel and passing through the sensor port.
While these conventional devices may be suitable for the particular purpose to which they address, they are cumbersome with respect to maintenance activities that include removal of a surface or element in contact with the fluid being treated, as interruption of flow to or draining of fluid from the treatment vessel is required to prevent inadvertent escape of fluid through the monitoring port.
It is, therefore, desirable to provide a novel rotating monitoring port assembly for a fluid treatment system.